1. Field of the Invention
The present invention relates generally to load retainer assemblies and load retaining apparatus which retain a load, such as a workpiece, by means of a plurality of suction pads to carry the thus-retained load to a desired place, and more particularly to an improved load retainer assembly and load retaining apparatus which allow the individual suction pads to be adjusted in position as desired.
2. Description of the Related Art
There are known various apparatus for retaining a load by means of suction pads to carry the load to a desired place, an example of which is disclosed in Japanese Patent Laid-open Publication No. HEI-7-206211 under the title of "Load Carrier Apparatus". The disclosed carrier apparatus includes a beam-shaped carrier body, and a pair of retaining frames connected to the carrier body in such a way that the retaining frames are movable, via associated electric motors, along the length of the body so as to adjust a distance between the two. On each of the retaining frames is mounted a suction pad holder for sliding movement on and along the retaining frame, and a disk-shaped suction pad is attached to each of the holders for adhering to and retaining a load by suction. Also, drive means, such as feed screws or motors, are provided on the retaining frames in order to move the respective suction pad holders.
However, in the disclosed carrier apparatus arranged as above, the retaining frames are each fixed in length (i.e., have an invariable length), and the retaining frames would often strike a wall or the like in a small working place, making the load carrying operations considerably difficult. Further, because the drive means, such as feed screws or motors, for moving the suction pad holders are provided on the retaining frames and the motors for adjusting the distance between the retaining frames are mounted on the carrier body, the carrier apparatus has a relatively great total weight, which would give a very heavy load on the driving and supporting mechanisms of the apparatus.